Field of the Invention
The present invention relates to wire bending. More specifically, the present invention relates to wire bending heads capable of on and off-plane nose and mandrel bends using the same machine.
Background of the Invention
Bending machines are used to create accurate and complex bends. Bending machines may be operated through computer numerical control (CNC). CNC benders allow a user to design a shape, and have the machine create a shape of consistent specification and quality. For instance, the creation of grocery carts requires many precise bends which are not easy to manually execute.
Wire bending machines are used with various kinds of wire. CNC benders feed wire directly from a coil stock to a bending mechanism. The size of the wire used in such machines can range in diameter, with no major tool changes necessary to interchange wire. Wire bending machines may be used to create precise parts.
Currently, many people bend wire using mandrel bending or nose bending styles. Current limitations exist with the amount of bending radii possible on a tool. Conventional nose bending has capabilities of one radius to four or even eight radii, depending on tooling. The tool used for nose bending is called a turret cluster. The turret cluster normally has 4 different radii, but in some cases may have 8 different radii for left or right bending.
Nose bending is a more robust style of bending, especially when using very small radii less than one-half of the wire diameter. The tool life remains robust because the tool is built from a strong material in the form of a triangle with enough material to support the bend. Nose bending is a process by which a wire is held between two holding pins, while a bending pin sweeps the wire to a side, bending it against one of the two holding pins. This is typically accomplished by feeding a wire through two holding pins. The bending pin is attached to a large block having more than one bending pin, which slides circumferentially about the two holding pins. Only one bending pin on the large block is engaged at a time. It can bend against either of the two holding pins, and can bend to virtually any angle. Two-dimensional nose bending is a common form of wire bending because the moving parts are kept to a minimum. Three-dimensional nose bending is possible with the addition of a bending head that rotates around a wire.
Mandrel bending has advantages such as being able to form a complete loop all the way around until the end of the wire touches the leading edge of the wire. A complete loop is formed in one motion as opposed to nose bending where a complete loop requires two or more motions. A mandrel-bending tool is usually smaller than a nose-bending tool. Mandrel bending has become more popular because it takes less time to form an entire loop than with nose bending. Nose bending can form loops, but it takes three or more bends, and the loop is not perfect. A “loop” made by nose bending has noticeable angles and edges around the perimeter. However, a mandrel-bending tool can only create a loop having a predetermined diameter. In order to make a loop having another diameter, another mandrel-bending tool will need to be used.
However, many combinations of nose and mandrel bends currently involve multiple machines or robot arms. For example, a double loop cannot be made without a robot arm. What is needed is a device capable of making both nose and mandrel bends, and also capable of off-plane bending without the use of an external arm or clamp.